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Chd|====================================================================
Chd|  CHECKSUM_MOD                  source/mpi/output/node_checksum.F
Chd|-- called by -----------
Chd|        SPMD_FLUSH_ACCEL              source/mpi/output/spmd_flush_accel.F
Chd|-- calls ---------------
Chd|====================================================================
      MODULE CHECKSUM_MOD
      INTEGER, PARAMETER :: ROOT = 65521
      INTEGER, PARAMETER :: TWO_POWER_16 = 65536
      CONTAINS
!! \brief Returns Adler32 checksum of A(1:SIZ2,1:SIZ1) 
      FUNCTION  DOUBLE_ARRAY_CHECKSUM(A,SIZ1,SIZ2) RESULT(CHECKSUM)
C-----------------------------------------------
C   I m p l i c i t   T y p e s
C-----------------------------------------------
#include      "implicit_f.inc"
C-----------------------------------------------
C   D u m m y   A r g u m e n t s
C-----------------------------------------------
      INTEGER, INTENT(IN) :: SIZ1,SIZ2 !< sizes
      DOUBLE PRECISION, INTENT(IN) :: A(SIZ2,SIZ1) !< 2D array of real values
      INTEGER :: CHECKSUM !< return value, Adler 32 checksum of A
C-----------------------------------------------
C   L o c a l  V a r i a b l e s
C-----------------------------------------------
      INTEGER, DIMENSION(:), ALLOCATABLE :: TMP !< temporary array
      INTEGER :: I,S1,S2
      INTEGER :: PREC ! simple or double precision
      INTEGER :: SIZ
C-----------------------------------------------
      S1 = 1
      S2 = 0
      PREC = 2
C  If A is in simple precision
      IF(SIZEOF(A(1,1)) == 4) PREC = 1
      SIZ = SIZ1*SIZ2 * PREC
      ALLOCATE(TMP(SIZ))
      TMP(1:SIZ) = 0
c     Convert A in integer
      TMP = TRANSFER(A(1:SIZ2,1:SIZ1),S1,SIZ)
      DO I = 1,SIZ
        S1 = MOD(S1 + TMP(I),ROOT)
        S2 = MOD(S1 + S2    ,ROOT)
      ENDDO
C     (s2 << 16) | s1
      IF(S1 < 0) S1 = S1 + TWO_POWER_16
      CHECKSUM = IOR(ISHFT(S2, 16), IAND(S1, (TWO_POWER_16-1)))
      DEALLOCATE(TMP)
      END
      END MODULE CHECKSUM_MOD

